BENTHIC RESPONSE TO WATER COLUMN PRODUCTIVITY PATTERNS - EVIDENCE FORBENTHIC-PELAGIC COUPLING IN THE NORTHEAST WATER POLYNYA

Polynyas, recurring ice-free areas amid pack or drift ice, are model s ystems for predicting the potential productivity of pelagic and benthi c communities in polar regions. The Northeast Water Polynya on the nor theast Greenland continental shelf and surrounding ice-covered areas w ere investigated to address the influence of water column processes on the benthos. We measured infaunal density, polychaete biomass, sedime nt carbon concentration, and benthic pigment concentration from replic ate box cores at 16 stations. Benthic pigment concentration is the mos t important predictor of infaunal density and polychaete biomass, expl aining nearly half of the variance in these variables. Benthic pigment concentrations are strongly related to the concentrations of water co lumn pigments, suggesting that the signal of water column productivity is received on the bottom and. transmitted to the fauna. The highest densities and biomass are found near the mouth of the Northern Trough and are probably fueled by biogenic material produced by the developin g phytoplankton community as it: is advected down the trough. Density and biomass are also generally higher under the ice-free water of the Northern Trough than under the ice-covered Southern Trough. This patte rn may be explained by greater primary productivity in the Northern th an Southern Trough and/or by a decoupling of water column and benthic process by zooplankton grazing in the south. Sediment organic carbon c oncentration is between 0.5% and 1.5%, indicating that the sediment is probably not an unusually large carbon sink relative tb shelf and dee p-sea systems in temperate and polar regions. These results reinforce an emerging pattern of efficient transfer of carbon from water column to benthos in high latitudes. Owing to the abundance of small-scale an d mesoscale areas of enhanced phytoplankton production in the Arctic ( e.g., leads, marginal ice zones), benthic biomass in the Arctic Ocean and surrounding seas may be higher than previously anticipated.